Measles and SSPE viruses will be isolated in relative purity from cell cultures and analyzed for total lipid content, including a detailed analysis of gangliosides and neutral glycosphingolipids. The host cell lipids will be similarly analyzed before and after infection to determine glycolipid alteration and the possibility of general reduction in acidic lipids. Ganglioside G2B, a species we previously detected in MS plaques but not normal white matter, will be further studied to ascertain its "marker" status for such plaques and to elucidate its structure. Cultured cells from explants of human gray matter, white matter and MS plaques will be analyzed for glycolipid composition and the possible presence of the G2B "marker". Gangliosides will be further studied in brain from chimpanzees infected with kuru and Creutzfeldt-Jakob agents. We shall attempt to determine whether the gross changes we previously observed are localized in a specific component of the CNS. We shall continue our study of G7 (sialosylgalactosyl ceramide), a ganglioside we discovered to be highly localized in CNS myelin. Its origin and potential role in myelin maturation will be investigated as well as the details of developmental and evolutionary changes.